Stretching machine



Jan. 16, 1934. R L, F N ET AL 1,943,794

STRETCHING MACHINE Filed March 12, 1931 3 Sheets-Sheet l mine. I venifors WWW @4 M MW%TM Jan. 16, 1934. R. L. GRIFFIN ET AL STRETCHING MACHINE Filed March 12, 1931 3 Sheets-Sheet 2 z? gig Jan. 16, 1934. R, GR|FF|N r AL 1,943,794

STRETCHING MACHINE Filed March 12, 1931 3 Sheets-Sheet 3 Patented Jan. 16, 1934 PATENT OFFICE STRETCHING MACHINE Roger L. Grifiin and James T. ONeil, Peabody, Mass, assignors to A. 0. Lawrence. Leather Company, Boston, Mass, a corporation of Maine Application March 12,. 1931; Serial No. 521 ,93

16 Claims.

The present invention relates to stretching:

machines and more particularly to power operated machines designed especially for stretching leather hides or skins.

One of the objects of the present invention is to provide a power operated machine of simple and inexpensive construction for stretching leather hides or skins or like materials in an expeditious and exact manner.

Another object of the invention is to provide a power operated machine whereby varying amounts of stretch may if desired be imparted to the material in different directions and in different portions thereof, according to the skill and judgment of the operator and dependent upon the size and character of the material and the results desired.

With these and other objects in view as will be apparent to those skilled in the art, the present invention consists of the devices and combinations of devices hereinafter described and claimed.

The invention in its preferred formisillus-- trated in the accompanying drawings in which Fig. 1 is a top plan view of the machine showing the expansible frame to which the hide or other material to be stretched is attached, with a detail of one" corner thereof showing the means of locking together two of its members; Fig. 2 is a front elevation of the machine with the expan-- sible frame removed; Fig. 3 is a vertical sectional view on line 3-3 of Fig. 2 on an enlarged scale of one of the stretching members, showing the means of its attachment to the body of the machine and means of its actuation; Fig. t is another sectional view of the same parts taken on line 4-4. of Fig. 3; Fig. 5 is a perspective of a corner of the stretching frame; and Fig. 6 is a schematic diagram of motors, controls and associated circuits employed in actuating the machine.

The apparatus illustrated in the drawings comprises a removable expansible frame within which the hide is secured and a machine for the plates 12 fashioned into abutments at their rear or inner edges, and each plate is provided with a plurality of holes continued into or through the members. Upon the ends of the members 11 are affixed metal brackets 13- pro-- videdwith a plurality of holes. These brackets permit-the insertion of the ends of the members 10 up to the abutments, and also permit sidewise displacement of the ends of the members 10. While the hide, secured to the expansible frame is held in a stretched condition, pegs may be inserted through holes in the metal brackets 13, metal plates 12, and frame members 10", 11', to maintain the stretched condition of the hide after the frame is releasedby' the stretching machine.

The hide or similar material tobe stretched is fastened inside of the frame in thecommorr and usual manner by means of toggles or clasps which may be of any of the well known and familiar constructions. These toggles grip the hide near its edge and are connected tothe frame by means of cords fastened incleats on the frame members.

Preparatory to mounting ahide in the frame, the pegs or pins will be removed and the frame will be contracted to its smallest perimeter so that the metal brackets of members 11 make contact with the ahutments of the plates 12' of members 10 and the inner edges of members 10- make contact with the inner walls of the brackets. The parts are their secured in position by the insertion of the necessary pegs. Preferably the contracted frame will be mounted upon a table or other suitable support While the hide is being toggled or mounted in the frameby means of the toggles, cords, and cleats; to'entend the hide flat and smooth under a generally uniform light tension in all directions, much less than when the stretchingis done by hand.

The contracted frame with the attached hide is now ready to be placed upon the stretching machine for the stretching. operation. This machine comprises four pairs of movable membersv or levers pivoted uponthemachine and arranged to: support. the stretching frame members. near each end and tospread. them apart, being actuated' by electric motors through suitable connections. Control devices in the form'- of operatoractuate'dl and automaticv switches are provided whereby the proper degree and direction: of stretch may be secured and the parts subsequently returned to initial position.

Two stretching levers are provided on eachof the four sides of the machine, one lever adjacent each corner on eachside; and opposite lovers are arranged to be actuated simultaneously by the same motor.

The stretching frame expanding members consists of eight substantially vertical arms or levers 21, pivoted at their lower ends 23 to the brackets 25 mounted on the side member of the frame of the machine. Each lever is formed with an outwardly facing shoulder 29 near its upper or free end adapted to receive and support one of the side members of the stretching frame. A convenient form of construction for these stretching levers is shown in Figs. 3 and 4 wherein the lever is made in two parts or halves, being divided on a vertical plane and the parts being secured together by bolts and nuts 31 and 33.

The lower end of the lever is bored to receive the vertical flanged stud 35 extending from the hub 37 through which passes the pivot pin 39 in bracket 25. Thus the lever has provision for both a swinging movement on pin 39 and also a rotational movement on stud 35 to give freedom in operation without liability of binding or crampin The levers are actuated in the swinging or stretching movements by means of shafts threaded at their outer ends and engaging nuts or internally threaded sleeves carried by the levers. The construction as shown in Figs. 3 and 5 comprises the threaded sleeve 41 having the trunnions 43 pivotally mounted in the sides of the lever. Protective sleeves or extensions 45 are provided, secured in each end of the threaded sleeve and a cap l? on the outer end of the outer extension, to avoid all possibility of the operators person or clothing or other material coming in contact with the machine and of injury or damage therefrom.

The threaded shafts for extending the stretch ing levers are arranged in pairs, each pair being adjacent one side of the machine and having threads of opposite directions at their outer ends. The shafts of each pair are positioned in the same vertical plane as shown in Fig. l, but at a slight angle to one another as shown in Fig. 2. By thus inclining the shafts, the driving motor and their reducing gearing and universal couplings may be spaced a sufficient distance below the work to avoid interference therewith, yet permitting the threaded ends of the shafts to engage and apply their power to the stretching levers close to the plane of the work.

In stretching 2. hide it has been found that While different degrees of lateral side stretch re often and in fact usually desirable at the shoulders and at the butts, the stretching longitudinally or lengthwise should be uniform on both sides. Therefore, in the present machine the lengthwise stretching members are arranged to be all simultaneously actuated by a single motor. Thus shafts 51 and 53 at one side of the machine and shafts 55 and 57 at the opposite side are driven from the same motor 59 through the speed reducing gear 61 and sprocket chains 63 and 65. Universal joints or couplings 6'? are provided on the inner ends of the actuating shafts to provide for the inclination of the same which will vary slightly during the operation of the machine.

The pairs of shafts for actuating the side stretching levers are each driven by a separate motor, shafts 69 and '71 from motor 73, and shafts '75 and 7'! from the motor 79. Reducing gearing and universal couplings are interposed between each motor and its pair of driven shafts.

The mechanism may be mounted upon any suitable framework, that shown comprising corner posts 81, top side members 83, and bottom cross members 85. Motor 59 is carried by the lower medial support 87, while motors '73 and 79 are mounted the upper support 89 held at each end the angle irons 91. Cross braces 93 near the middle of the upper support carry the bearings for the sprocket shafts 95.

If desired, a table 97 may be provided for supporting the skin while it is being toggled or mounted in the frame, or is being taken off, if either or both of op-:ations are done while the frame is on stretching machine.

In order to secure the desired results in the stretched skin, of the motors must be under independent control so that varying amounts of stretch may be given different portions. To expedite the operation of the machine, however, provision is whereby a uniform simultaneous initial stretching movement may be imparted to all of the stretching levers by means of a common control for all these motors. The return or reverse movement of the parts is similarly effected simultaneously by means of a common control of all the motors.

The circuits and controls are illustrated schenatioally Fig. comprise a three phase current supply indicated by the leads A, B and C, the three moto s marked 59, 73 and 79, the three forward magn tic starters one for each motor indicated at iii-S and FMS the generating magnets therefore FOM, FOB/l and FOM the three reverse magnets starters RMS, RMS and Pull 5S the operating magnets therefor ROM, ROE/l and ROD/l the forward magnetic starter for operating all three motors simultaneously FMS, and the operating magnet therefor FOM; four push button controls for the forwarc starters, one PB for the simultaneous operation of the three motors and one for the additional operation of each motor indicated at PB, P3 and P3 a single push button control PBR for the simultaneous operation of all three reverse starters, three cam operated forward and reverse limit switches 101, 103 and 105,

one for each of the motors 59, Z3 and 79.

The electrical connections between the various parts are clearly shown on the diagram and do not require detailed escription. The limit switches are located as shown in Figs. 1 and 2 and are actuated by the motors through sprockets and chains. These limit switches are of a well known type and consist of means for circuit breaking by worm gear driven cams.

The push button controls are located at some convenient position for the operator where he can stand and observe the stretching as it progresses. The connection through each of the four forward movement push buttons is such that each must be held depressed in order to maintain its operating magnet or magnets energized, and its forward magnet starter or starters in operation to supply current to its motor or motors. Upon release of each button, the motor or motors controlled thereby i'nmediately stop, but may be started again by depressing the proper button.

The connection through the single reverse button and the reverse operating magnets are such that once the button is depressed, and the control over each and all of the motors during the stretching" operation and may operate them concurrently or consecutively and to any extent desired.

After the stretching has been completed and the stretching frame has been secured in its expanded position, the operator has only to depress momentarily the single reverse button, whereupon all three motors are set in reverse operation and each continues until it is independently stopped by its reverse limit switch.

In operation the frame will ordinarily be mounted in contracted condition on a suitable table or support and the hide is toggled by means of the toggles and their attaching cords. The frame is then placed upon the machine with the side members of the frame on the shoulders 29 and the backbone of the hide, i. e. its longitudinal axis from neck to tail parallel to the pairs of shafts actuated by the single motor. The locking pegs being removed, the operator depresses button PB which controls all of the motors, and thereupon all of the stretching levers move outwardly simultaneously and uniforminly to exert a preliminary stretching of the hide. When sufficient preliminary stretch has been imparted, button PE is relaxed and the other proper buttons are depressed tostretch the hide lengthwise, or transversely at the neck or at the butt as may be required. These differential stretchings may be done simultaneously or consecutively as the operator desires, and in the direction and amount as the operator in his judgment shall deem advisable, until the hide has been properly stretched.

The buttons all being released, the motors remain stationary, and while the frame is held separated, the operator inserts the pegs into the corner plates and brackets, thus locking the frame in its expanded condition. A momentary depression of the reverse button by the operator starts the parts automatically back to their original positions ready for another frame and hide. As soon as this reverse movement begins and the pressure of the levers on the frame is released, the frame and its hide may be removed from the machine for drying or other treatment.

Thus a hide may be stretched by power stretching devices in an expeditious and exact manner under the full control and judgment of the operator, according to the character of the hide, its intended use, etc.

While the present invention has been shown and described as embodied in a machine for stretching hides, it is understood that it is not necessarily limited thereto but may be embodied in machines for stretching other materials. Nor is the present invention limited to the particular form and arrangements herein shown and described but may be embodied in other and different forms and combinations within the language of the claims.

Having thus described the invention, what is claimed is:

1. A stretching machine having, in combination, a pair of threaded shafts angularly disposed with relation to one another and to the plane of the work, a pair of movable stretching members having threaded connections with the shafts adjacent the plane of the work, and power actuated means spaced from the plane of the work for rotating said shafts to actuate the stretching members.

2; A stretching machine having, in combination, a pair of threaded shafts located in a plane transverse to the plane of the Work and angularly disposed to one another and to the plane of the work, a pair of pivoted stretching mem bers, pivotal supports therefor, means cooperating with the threaded shafts and connected with the members adjacent the plane of the work, and power driven devices spaced from the plane of the Work for rotating the shafts to actuate the stretching members.

3. A stretching machine having, in combination, a plurality of pairs of threaded shafts, the shafts of each pair being located in the same plane and angularly disposed to one another and to the plane of the work, pivoted stretching m mbers, pivoted supports therefor, connections between the shafts and said members adjacent the plane of the work, and power driven means spaced from the plane of the work for actuating the shafts in pairs.

4. A stretching machine having, in combination, a table, stretching members positioned at the margins of the table, power-driven means beneath the table and spaced therefrom, and :1

inclined threaded shafts connected with the members adjacent the table for actuating the members from said means.

5. A stretching machine having, in combination, stretching members, a plurality of pairs of 1 oppositely threaded inclined shafts connected to the members, a motor for actuating each pair of shafts, and reduction gearing and universal couplings between the motor and shafts.

6. A stretching machine having, in combinacured together to form a horizontal recess therethrough and a vertical cylindrical recess at one end, a threaded nut pivotally mounted in the horizontal recess, a horizontally pivoted support having a substantially vertical bearing stud received in the cylindrical recess in the end of the member, a threaded shaft engaging the nut, and means for actuating the shaft.

8. A stretching machine having, in combination, a plurality of pairs of stretching members and pairs of shafts for actuating the same,

motors for driving the shafts, a single control for operating a plurality of motors in one direction, a second single control for operating said motors in the opposite direction, and separate controls for each motor to operate the same independently of the other in one direction.

9. A stretching machine having, in combination, a plurality of pairs of oppositely disposed stretching members, motors for actuating said pairs of members, and controlling devices for operating a plurality of motors simultaneously in one direction to actuate the stretching members to an extent determined by the operator and in the other direction to return the members to a predetermined position.

10. A stretching machine having, in combination, a plurality of pairs of oppositely disposed stretching members, motors for actuating said pairs of members, and controlling devices for use operating a plurality of motors in one direction simultaneously or independently at the will of the operator and to a non-predetermined extent, and simultaneously in the opposite direction to a predetermined extent.

11. A stretching machine for expanding a stretching frame having, in combination, a stationary machine frame, a plurality of stretching members pivoted on the machine frame, each member having a shoulder to support the stretching frame, an internally threaded nut pivoted on each member to turn on an axis parallel to the axis of movement of each memher, and a threaded shaft engaging the nut for actuating the same.

12. A stretching machine having, in combination, a stationary frame, a plurality of stretching members pivotally mounted at one end on the frame, each member being provided with a recess therethrough, an internally threaded nut pivotally mounted in the recess of each member to turn about an axis parallel to the axis of movement of the member, a threaded shaft engaging each nut, and means including a universal coupling for actuating each shaft.

13. A stretching machine having, in combination, a stationary frame, tWo groups of stretching members pivotally mounted on the frame, the axes of the members of one group being parallel to each other and at right angles to the axes of the members of the other group, threaded shafts and connections for actuating the members, and means for rotating the shafts.

14. A stretching machine for expanding a stretching frame having, in combination, a machine frame, a table carried by the frame, a plurality of pairs of stretching members pivoted at their lower ends to the frame of the machine with their upper ends adjacent the edges of the table and projecting thereabove to engage and expand the stretching frame, and means carried by the machine frame and positioned beneath the table for actuating the stretching members.

15. A stretching machine for expanding a stretching frame having, in combination, a machine frame, a table carried by the frame, stretching members carried by the machine frame and projecting above the table to engage and expand the stretching frame, actuating devices positioned beneath the table for the stretching members, plurality of electric motors positioned beneath the table for driving the actuating devices, and supports carried by the machine frame at different levels for the motors.

16. A stretching machine for expanding a stretching frame having, in combination, a machine frame, a plurality of pairs of opposed stretching members carried by the machine frame, actuating devices for the stretching members, a pair of electric motors carried by the frame for actuating the devices to expand the stretching frame in one direction, and a separate motor carried by the frame at a different level from said pair of motors for actuating the devices to expand the stretching frame in a direction at right angles to said first mentioned direction.

ROGER L. GRIFFIN. JAMES T. ONEIL. 

